The invention discloses a silicon nitride ceramic artificial hip joint, which consists of an acetabular cup, an acetabular lining, an artificial femoral head and a femoral stem, and relates to the technical field of artificial joints. The acetabular cup, the acetabular lining, the artificial femoral head and the femoral stem are all made of silicon nitride ceramic materials, so that the acetabularcup, the acetabular lining, the artificial femoral head and the femoral stem not only possess various excellent performances of bioceramic implant but also have the advantages of high hardness, highbending strength, high fatigue strength and high fracture toughness, excellent friction performance, good bone length and bone growth capability, good anti-infection capability and good developability, and can improve the abrasion and stress shielding problems of the artificial hip joint. Wherein the outer peripheral surface of the acetabular cup and the surface of the femoral stem part are provided with porous rough structures, and biological fixation of the artificial hip joint can be enhanced by arranging the porous rough structures; an extension part is formed at the bottom edge of the acetabular lining, and the dislocation of the artificial hip joint can be prevented by arranging the extension part.